The present invention concerns a telewriting device enabling exchange of graphics and voice information with another such device communicating via an external data communication line, for example a telephone line.
There already exist autonomous telewriting devices which combine in a single casing a telephone and a tablet for writing and displaying data. The tablet is in the form a flat display screen associated with an input device enabling direct writing on the screen using a stylus. The traces made by the stylus on top of the screen appear directly on the screen and are also sent to another similar device connected to the communication line where they are reproduced identically. These traces can be superimposed on another display of information from a source external to the writing tablet and present on the screen of each of the connected devices. The display of manuscript traces (telewriting data) can be a text or a drawing to be commented on, for example, the traces made by the stylus can provide a visual indication of required changes or can even effect such changes.
The display from the external source (external relative to the writing tablet) can come from various peripheral devices or from devices integrated into the telewriting device: a memory unit (diskette, hard disk, optical disk), a computer, a scanner or a keyboard. In normal use display data from the external source is loaded onto a single telewriting device either by transfer within the device or by means of a cable connecting it to a peripheral device. It is then sent to one or more other devices communicating via the external data communication line during the connection.
Telewriting devices of the above type are described in documents U.S. Pat. No. 5,521,335, U.S. Pat. No. 5,508,713 and EP-A-0 379 354, for example.
Sending of data for display from an external source is relatively time-consuming and constraining, in the case of information which is often dense, especially if it includes graphics, and is likely to be renewed during a call, for example to go from one page to another. The data can be sent in packets, however, subject to a slight increase in sending time.
In contrast, data entered in writing, consisting of fine traces that evolve progressively, can be sent relatively rapidly. However, from the point of view of user friendliness it is important for the lines to be displayed on the receiving device at virtually the same time as they are made on the sending device, i.e. in real time.
Prior art telewriting devices are not specifically designed to allow for these constraints. They are therefore limited in their capability to send simultaneously traces and graphics from external sources or incapable of real time bidirectional communication between devices.
With other types of telewriting device based on personal computers or fixed stations it is feasible to improve the flow of information by using complex data communication algorithms, but this is at the cost of the mobility and the autonomy of the equipment.
Accordingly, the invention consists in a telewriting device forming an autonomous and integral unit that overcomes the problems encountered in devices known until now by enabling two-way (real time full duplex) exchange of voice and graphics data, in particular data entered in writing, with optimal control of data from external sources.
This aim is achieved thanks to an in-depth investigation by the applicant of the sources of the limitations of the prior art techniques, which has lead to a new architecture that is specifically optimized while remaining simple to implement.
The telewriting device of the invention is of the type comprising means for exchanging voice data, display means having a display surface, means for input by writing on the display surface and interface means assuring the exchange of input and output data over an external data communication line.
The invention provides a telewriting device enabling exchange of graphics and voice information in real time with another such device communicating with it via an external data communication line, the device comprising to this end:
means for exchanging voice data,
display means having a display surface,
means for receiving manuscript traces for real time display of traces on the display surface,
means for processing the manuscript trace (telewriting) data and other data to be exchanged, and
interface means for exchanging the manuscript trace data and said other data over the external data communication line.
In the telewriting device of the invention, the data processing means comprise:
a first control unit for managing said other data, said first control unit being connected to the interface means by a first link dedicated (i.e. specific) to this first control unit for exchange of said other data over the external data communication line, and
a second control unit that can operate in parallel with the first control unit for controlling the manuscript trace receiving means, said second control unit being connected to the interface means by a second link dedicated specific to this second control unit and enabling exchange of manuscript trace data over the external data communication line.
Thus, the different tasks are divided optimally between the first and second control units for parallel processing of the other data from input and output devices and the manuscript trace data. What is more, the use in accordance with the invention of separate dedicated links between the interface means and the first and second control units assures the real time flow of manuscript trace data via the second control unit whilst maintaining at all times communication with the first control unit.
This unit can therefore monitor at all times the operational status of the external line and the interface means. It is then easy to exchange data with the interface means over the first link and the second link in a shared access mode using a predetermined protocol without disturbing the flow of manuscript trace data.
Note that manuscript trace data also includes commands associated with the functions of manuscript input on the screen: selection with the stylus of parts of the display (words, blocks), deleting, moving, copying selected parts, etc., as in a word processor
Note that the term xe2x80x9cother dataxe2x80x9d can include all data, apart from that arriving in real time from the manuscript trace receiving means, to be managed by the telewriting device. This xe2x80x9cother dataxe2x80x9d is generally graphics data. The other data may e.g. includexe2x80x94although not exclusivelyxe2x80x94document pages to be displayed on the screen on a device in receive mode or in send mode. These document pages can come from sources external to the telewriting device, such as storage peripheral devices, data processing equipment, etc.
It can equally come from storage units internal to the device (diskette or hard disk drive, CD-ROM etc.), depending on implementation choices.
In preferred embodiments of the invention the other data does not include telephone voice data or facsimile data. These latter types of data are advantageously managed within the interface means.
In receive mode, the other data received can be displayed on the screen either immediately or later (for example in response to a request). It can also be stored on internal or external devices or sent to other equipment connected to the device, for example a printer, a monitor, a personal computer, an electronic organizer, etc.
It is then possible to assign priority for access to the interface means to one of the control units, for example the second one, to assure that the exchange of traces input is always effected in real time, even if the device is sending or receiving other data to or from a device over the external line, for example to download a document. In this case the data entered in writing can be exchanged (sent or received) over the second link in real time and at any time. If it is necessary also to convey data managed by the first control unit, for example pages for display read out of a memory, while manuscript trace data is being exchanged, the former is sent only during gaps in the flow of manuscript trace data, in accordance with an interleaving protocol.
The effect of having two control units with separate tasks in accordance with the invention achieves very efficient exchange of data over the first and second links as the computation and management process on the upstream side of each link is active at all times.
In a preferred embodiment of the invention the device is operational when the other data constitutes a document to be displayed on a receiving device and occupies more than one display page on the screen to assure in order of increasing priority: i) sending of some of said other data constituting a display page on the screen, ii) exchange of telewriting data, and iii) sending of the remainder of said other data to enable superimposition of data entered in writing on a document page displayed as soon as it is received.
This mode of operation is useful if the data entered in writing exchanged concerns traces or other annotation to be superimposed on a document page shown on the connected devices.
In this way, the superimposition of the manuscript trace data on a document page is displayed as soon as it is received. A telewriting dialogue can therefore begin without waiting for the complete document to be loaded into the receiving device.
After the first page of the document is loaded, the remaining pages can be loaded into the receiving device during free periods in the sending of telewriting data.
To enable optimum management of this preferred embodiment of the invention the first and second links exchange data via the interface means in a shared access mode on the external data communication line in accordance with a predetermined protocol.
The device advantageously comprises means for interleaving data entered in writing and other data to assure real time sending of manuscript trace data over the external data communication line.
Note that in a combined mode of sending other data and data entered in writing this preserves the priority of sending data entered in writing, other data (for example pages of a document to be downloaded following on from the first page) being sent as a background task under the control of the first control unit.
Said other data is preferably in the form of successive data blocks. Interleaving can then be effected by inserting manuscript trace data into gaps a between blocks of said other data, the manuscript trace data comprising a single pixel, a group of several pixels or a command relating to the written input function.
In one advantageous embodiment of the invention each pixel of a series of consecutive pixels is written into a respective gap between the blocks of other data that follow on in succession in accordance with the normal bit rate of the pixels from the written input means. In the current state of the art this choice achieves an excellent compromise between the imperative of assuring sufficiently fast sending of pixels for real time full duplex display of writing on a receiving device and prompt loading of the remaining pages.
If manuscript trace data to be sent to the external data communication line appears during sending of other data to this line, interleaving is advantageously started at the first gap between two successive blocks of other data after the appearance of the manuscript trace data.
When interleaving with other data in the form of blocks, the blocks preferably occupy a time period equal to or less than the gap between consecutive manuscript trace data. The interleaving of the data then has practically no effect on the exchange of information received by users.
In the embodiment that will be described by way of example, the means for interleaving data are implemented in the first control unit, the manuscript trace data and the other data interleaved with it being sent over the first dedicated link to the interface means for sending over the external data communication line.
Note that in this context the expression xe2x80x9cother dataxe2x80x9d covers all the interleaved data sent by the first control unit.
In this embodiment, the second control unit can exchange and process telewriting data from another device communicating via the interface means and the second dedicated link concomitantly with sending of data by the first control unit via the interface means and the first dedicated link.
The interface means can send and receive data in full duplex mode over the external data communication line, the sent data and the received data being either interleaved or not.
In the case of normal use of the device, the full duplex exchange of data is effected:
i) either by receiving and sending non-interleaved data. This is e.g. the case in particular if two (or more) devices communicating with each other simultaneously exchange manuscript trace data when no other data is being sent;
ii) or by sending interleaved data and receiving non-interleaved data. This is the case e.g. when a telewriting device sends simultaneously manuscript trace data and other data, this other data possibly relating to pages of a document beyond the first page (remaining pages). Note that the interface means of the device communicating with the device operating in the aforementioned mode will operate in the opposite mode, i.e. receiving interleaved data and sending non-interleaved data. Of course, each telewriting device will be capable of operating in either of these two opposite modes.
The present invention also makes it feasible to envisage full duplex communication between two (or more) telewriting devices by sending and receiving interleaved data.
This mode of operation could apply, for example, to an interactive document updating mode of communication. The initiating device then sends to the receiving device interleaved data representing the manuscript trace data and the other data.
The receiving device could then send in fall duplex mode another document (for example for archive storage on a fixed storage unit of the initiating device) while this communication is in progress.
In this case, the communication time can be exploited to send this other document because this will be effected concomitantly with the operation of interactively updating the document of the initiating device. The user of the receiving device will then not need to wait for the end of the command for interactive updating of the document to send the document to the initiating device. This optimizes the use of communication time and therefore operating costs.
In a first embodiment of the present invention the data is interleaved in the first control unit, the manuscript trace data and said other data being sent in interleaved form over the first dedicated link to the interface means for sending over the external data communication line.
In this mode, the first control unit can also monitor the interface means and access to it via the second link.
Alternatively, in a second embodiment, the data can be interleaved at the level of the interface means, the other data and the manuscript trace data being sent to the interface means over the first link and the second link, respectively.
This variant provides all the functional possibilities mentioned above and the attendant advantages. The data received by the telewriting device can then be sent by the interface means to one or other of the first and second control units, or to both of them simultaneously.
If the received data is interleaved, comprising both other data (for example display page data) and telewriting data, the interface means divides up the interleaved data using a demultiplexer in order to send the other data over the first dedicated link and the telewriting data over the second dedicated link, respectively. In this case, the telewriting device will include means for monitoring the flow on the first and second links in order to assure bidirectional communication on them. This flow control is advantageously based on time sharing the first and/or the second link.
These control means can be in the first control unit or in the interface as means.
The interface means preferably assure the exchange of voice data by telephone microphone and earpiece means connected to it independently of the first and second links.
In this second embodiment, if said other data and the manuscript trace data are concomitant for sending over the external data communication line, access for the manuscript trace data to the interface means via the second link has a higher priority in order to assure its real time communication.
More generally, and regardless of the aforementioned embodiment, the interface means preferably send interleaved data in full duplex mode and receive data on the external data communication line.
There is advantageously also a bidirectional link between the first and second control units. This bidirectional link enables direct exchange of control data between the two control units without disturbing the flow of data exchanged with the interface means.
The bidirectional link enables exchange of data concerning the busy status of the first and second dedicated links, interrupt requests (for priority access), and control instructions or display data, for example for storage on a memory unit managed by the first control unit.
With this architecture it is possible to confer on the first control unit the task of monitoring the interface means and access to them via the second dedicated link.
Means for monitoring dialogue between the first and second control unit on the bidirectional link are preferably provided, such means comprising: a storage area specific to each of the control units for the data exchanged, each of the storage areas being read only by one of the control units and written only by the other control unit, means indicating to a destination control unit the presence of data in its storage area written by the sending control unit, and means for indicating to the sending control unit the reading of data in the storage area of the destination control unit.
The dialogue monitoring means can further comprise means for prohibiting writing of data in a storage area if it already contains data that has not been read.
Of course, the first and second control units can be used to manage additional tasks over those already mentioned. In a preferred embodiment of the invention the first control unit will be employed mainly to monitor telewriting device input and output. In this regard, it can manage at least one of the following peripheral or internal devices: removable data storage means, fixed data storage means, a printer and a serial link.
The second control unit is preferably dedicated to functions concerning the applications of the telewriting device. This naturally concerns functions associated with telewriting input and preferably functions associated with display of data whether this is manuscript trace data or pre-existing display data, together with commands relating to these functions. Depending on the possible configurations, it can also assure the management of at least of the following devices: a document scanner, a device for reading and/or writing data on a data storage card, such as a smart card, a fingerprint reader and a keyboard.
The interface means advantageously comprise their own means for routing and monitoring on the external line sending or receiving of data exchanged over the first and/or second link and sending or receiving of voice data on a time-sharing basis.
The telewriting device of the invention is designed to operate on conventional telephone lines (switched lines) or digital lines (for example ISDN Lines). In this case, the interface means will advantageously be provided with means enabling them to operate on both these types of line.
In this regard, the interface means preferably comprise means for digitizing voice data in accordance with a predefined protocol.
The present invention also concerns a method of controlling a telewriting device enabling exchange of graphics and voice information in real time with another such device communicating with it via an external data communication line, the device comprising:
means for exchanging voice data,
display means having a display surface,
means for receiving manuscript traces (telewriting) for real time display of traces on the display surface,
means for processing manuscript trace data and other data to be exchanged, and
interface means assuring exchange of manuscript trace data and said other data over the external data communication line,
said method consisting in dividing the tasks of the data processing means to assure in parallel:
on the one hand management and exchange of said other data over the external data communication line by the interface means, and
on the other hand management and exchange of manuscript trace data over the external data communication line via the interface means.
When the other data constitutes a document to be displayed on another such device and occupying more than one display page on the screen, said means for processing manuscript trace data and said other data are preferably controlled so as to assure in order of increasing priority: i) sending of some of said other data constituting a display page on the screen, ii) exchange of telewriting data, and iii) sending of data of the remainder of said other data, to enable superimposition of manuscript trace data on a displayed document page as soon as it is received.
In a preferred embodiment of the invention, when the other data and the manuscript trace data must be sent simultaneously, they are sent in shared access mode over the external data communication line. This sharing mode is preferably implemented by interleaving to enable real time sending of manuscript trace data over the external data communication line.
Said other data is preferably in the form of successive blocks of data. Interleaving can then be effected by inserting manuscript trace data into the gaps between blocks of said other data, the manuscript trace data comprising a single pixel, a group of pixels or a command relating to a telewriting input function.